The invention concerns an electronic control system for magnetic valves which are operated individually or in cascade.
Different drives can be used for the actuation of valves. Valves can be provided with a magnet drive for controlling low outputs, while higher outputs require a hydraulic drive. Accordingly, with lower output requirements a magnetic valve operated individually can be electrically adjusted by means of a regulator. With higher output requirements a magnetic valve is connected upstream of a hydraulically actuated main valve and the pressure medium for actuating the main valve is controlled via the magnetic valve. Together with the main valve, the magnetic valve forms a valve cascade in which the magnetic valve is operated as a pilot valve. The regulating voltage put out by the regulator does not act directly on the main valve which is actually to be adjusted, but rather is applied to the controlling magnet of the magnetic valve. A regulating voltage can be derived from a comparison between the reference value and actual value of the position of the main valve, which regulating voltage controls the magnetic valve connected upstream in such a way that the valve position of the main valve is adjusted to the reference value.
The electronic control system used to generate the regulating voltage is usually accommodated in a control unit arranged separately from the valves. Depending on the type of valve--individually operated magnetic valve or valve cascade including pilot valve and main valve--different circuit arrangements are used for the two different types of control. This has the disadvantage that the construction of the electronic control system must be adapted to the respective operating type - individual operation or pilot operation.